Big-titted female college students, Suzuka and Haruka, are attending a special seminar at a hot spring inn during summer break. Despite still being students, their professor carefully instructs them on sexual knowledge to help them survive in the adult world. His teaching methods are intense, and gradually the two grow accustomed to promiscuous sex. Even after becoming working adults, they continue seeking nighttime pleasures in between jobs, and their hearts grow increasingly immersed in lust.